Inhalation device

ABSTRACT

A medication inhalation device includes a housing having a through-going pathway connecting an air inlet with an air outlet, a medicament reservoir adapted to receive a compacted body of powdered medicament, and metering means for dispensing a predetermined dose of medicament from the reservoir into the through-going pathway, the metering means including means for abrading the compacted body; the device is provided with a shutter movable between a first position in which the compacted body is isolated from the through-going pathway and a second position in which the compacted body is in communication with the through-going pathway wuch that a dose of medicament can be dispensed from the reservoir into the through-going pathway.

This invention relates to a device for the administration of powderedmedicaments by inhalation, more particularly to a multiple-doseinhalation device with metering means for dispensing pre-determineddoses from a medicament reservoir.

European Patent Application 407028 (Fisons plc) discloses amultiple-dose inhalation device in which a dose of medicament is meteredby abrading a fixed volume from a compacted body of powdered medicament.The metered dose is then entrained in a through-going pathway of thedevice and is inhaled by the patient, the means for abrading being, forexample, a helical blade. Other devices which use the principle ofabrading a compacted body of powdered medicament are disclosed inInternational Patent Applications WO 92/04067 (Boehringer Ingelheim KG)and WO 93/24165 (GGU Gesellschaft fur Gesundheits- und UmweltforschungmbH & Co. Vertriebs KG).

Such devices may offer improved dose consistency when compared tomultiple-dose devices which rely on gravitational force to meter a doseof medicament from a reservoir. However, inaccuracies in dosing maystill occur due to incomplete removal of the abraded dose from thecompacted body, or by the removal of additional quantities of powderfrom the body during inhalation by the patient. Furthermore, if suchdevices are inadvertently dropped quantities of medicament could breakoff from the compacted body and enter the through-going pathway of thedevice, resulting in a multiple dose being administered when the patientnext uses the device.

We have now found that these disadvantages can be overcome orsubstantially mitigated by providing a shuttering system in the devicewhich is capable of isolating the compacted body of medicament from thethrough-going pathway of the device.

Thus, according to the invention, there is provided a medicamentinhalation device including a housing having a through-going pathwayconnecting an air inlet with an air outlet, a medicament reservoiradapted to receive a compacted body of powdered medicament, and meteringmeans for dispensing a predetermined dose of medicament from thereservoir into the through-going pathway, the metering means includingmeans for abrading the compacted body; characterised in that the deviceis provided with a shutter movable between a first position in which thecompacted body is isolated from the through-going pathway and a secondposition in which the compacted body is in communication with thethrough-going pathway such that a dose of medicament can be dispensedfrom the reservoir into the through-going pathway.

The means for abrading the compacted body preferably includes a bladewhich cuts, planes, scrapes or otherwise erodes a surface of thecompacted body by relative rotation or sliding between them. Forexample, the blade may have a helical shape, in which case the doseabraded from the compacted body of medicament will depend inter aliaupon the pitch of the helix, the diameter of the blade, the density ofthe compacted body, and the angle through which the blade is rotated.Alternatively, the means for abrading the compacted body may include abrush or other abrasive surface.

The shutter is preferably biassed into the first position in which thecompacted body is isolated from the through-going pathway.

The shutter may be mounted on a carrier, the carrier being adapted tomove within the housing of the device, e.g. in an axial direction.Movement of the shutter between the first and second positions may thenbe effected by the action of a cam on the carrier. The carrier ispreferably kept in contact with the cam surface by biassing means, e.g.a cantilever, provided on the carrier which bears against a stationarypart of the device. The cam is preferably arranged such that the shuttermoves from the first position to the second position prior to themetering of a predetermined dose of medicament from the reservoir, andreturns to the first position once the predetermined dose of medicamenthas been metered. In addition, the shutter preferably returns to thefirst position before the patient inhales the dose of medicament fromthe device.

When the shutter returns to the first position before the patientinhales the dose of medicament from the device, the shutter ispreferably adapted to sever the metered dose of medicament from thereservoir upon moving from the second position to the first position.The dose of medicament is then deposited in a holding chamber located inthe through-going pathway, where it stays until the patient inhales fromthe device. When the shutter is adapted to sever the metered dose ofmedicament from the reservoir it preferably comprises a metal blade.

The through-going pathway of the device may also include a dispersionchamber located between the holding chamber and the mouthpiece. Thedispersion chamber may be provided with tangential air inlets whichserve to provide a swirling flow of air in the chamber thus assistingthe dispersion of the medicament.

The shutter movement and metering operations may be controlled by adrive mechanism located within the device.

The drive mechanism is preferably associated with a drive sleeverotatably mounted on the housing of the device. Rotation of the drivesleeve causes rotation of a cam which is translated into the axialmovement of the carrier and shutter, and also the relative movement ofthe metering means and the compacted body of medicament required forabrasion of the compacted body. In this manner the shutter movement andmetering operations may be performed sequentially in response to asingle action by the patient. The degree of rotation and hence theamount of medicament abraded is preferably controlled by rotationcontrol means, for example a ratchet associated with the drive meansand/or stops provided on the housing, which will only permit rotationthrough a predetermined angle for each dose.

The shutter carrier can conveniently be configured such that it largelyseparates the drive mechanism for the device from the through-goingpathway. This has the advantage that it reduces the risk of ingress ofmedicament into the drive mechanism.

Compacted bodies of powdered medicament include bodies of medicamentproduced by compressing a sample of loose powder so that the medicamentparticles hold together. The degree of compaction obtained will clearlydepend upon the compression force applied to the sample of loose powder,as described in European Patent Application 407028 (Fisons plc), thedisclosure of which is hereby incorporated by reference. However, ingeneral, the degree of compaction will be sufficient to impart saidcompacted body with structural integrity such that a plurality of unitdoses of medicament can metered therefrom by abrasion.

The compacted body of inhalation medicament may have any convenientexternal shape, for example cylindrical or brick-like. However, weprefer the compacted body to have an annular configuration. Annularcompacted bodies of medicament may be made by the method described inInternational Patent Application WO 94/00291 (Fisons plc), thedisclosure of which is hereby incorporated by reference.

Medicaments which may be administered from the device according to theinvention may include any active ingredients which are conventionallyadministered by inhalation in powdered form. Such active ingredientsinclude drugs for use in the prophylactic or remedial treatment ofreversible obstructive airways disease. Specific active ingredientswhich may be mentioned include salts of cromoglycic acid, e.g. sodiumcromoglycate; salts of nedocromil, e.g. nedocromil sodium; inhaledsteroids such as beclomethasone dipropionate, tipredane, budesonide andfluticasone; anticholinergic agents such as ipratropium bromide;bronchodilators, e.g. salmeterol, salbutamol, reproterol, terbutaline,isoprenaline and fenoterol, and salts thereof. If desired a mixture ofactive ingredients, for example, a mixture of sodium cromoglycate and abronchodilator, such as salbutamol, reproterol, isoprenaline,terbutaline, fenoterol or a salt of any one thereof, may be used.

The devices according to the present invention may be designed forlimited use, i.e. they may be supplied with an integral compacted bodyof medicament, the device being discarded when this is exhausted; orthey may be reusable, i.e. replacement compacted bodies may be providedfor insertion into the device.

Thus, according to a further aspect of the invention we provide a deviceas described above, wherein the medicament reservoir contains acompacted body of powdered medicament.

The devices of the present invention overcome the disadvantages of priorart devices in that the dosing consistency is improved because theshutter severs the dose cleanly at the end of the dose abrasionoperation; they prevent the patient back-breathing onto the compactedbody of medicament thereby providing improved moisture protection forthe medicament; they are easier to use. Furthermore, since the shutterisolates the compacted body of medicament from the through-going pathwayduring inhalation, it prevents the patient inadvertently inhalingadditional drug out of the reservoir.

Although the invention has been described for use in oral inhalation ofmedicaments, it is also suitable for the administration of nasalmedicaments by inhalation. The necessary adaptation for this mode ofadministration will be readily apparent to those skilled in the art.

A preferred embodiment of the present invention will now be described,by way of example, with reference to the following drawings, in which:

FIG. 1 is a longitudinal view in partial section of a device accordingto the present invention in the first/rest position (dispersion chambernot illustrated);

FIG. 2 is a longitudinal view in partial section of the device of FIG. 1in the second/metering position;

FIG. 3 is a longitudinal section showing in detail the shutter,reservoir and through-going pathway of a device according to theinvention in the first/rest position;

FIG. 4 is a longitudinal section of the device of FIG. 3 in thesecond/metering position;

FIG. 5 is a partial section of the shutter and reservoir of the deviceof FIG. 3 along the line V--V; and

FIG. 6 is a partial section of the shutter and reservoir of the deviceof FIG. 4 along the line VI--VI.

A device according to the invention includes a housing (1) having athrough-going pathway (2) connecting an air inlet (3) with an air outletin the form of mouthpiece (4) having a mouthpiece cover (not shown). Adispersion chamber (5) having tangential air inlets (6, 6a) is locatedin the through-going pathway between air inlet (3) and mouthpiece (4).

A generally cylindrical medicament reservoir (7) containing an annularcompacted body of powdered inhalation medicament (8) is rotatablymounted on the housing (1) adjacent to the through-going pathway (2)upstream from the dispersion chamber (5).

A shutter (9) comprising a metal blade (10) is mounted on a carrier (11)which is adapted to move axially within the housing between a first/restposition FIG. 1! in which the compacted body (8) is isolated from thethrough-going pathway (2), and a second/metering position FIG. 2! inwhich the compacted body (8) is in communication with the through-goingpathway (2). The end of carrier (11) remote from the shutter (9) isprovided with a lug (12) adapted to interact with a cam (13) provided onthe inside of a drive sleeve (14) rotatably mounted on the housing (1).The carrier (11) is biassed against the cam (13) by a half cantilever(15) provided on the carrier (11) which bears against an exterior wallof the dispersion chamber (5). The end of the carrier (11) remote fromthe shutter (9) is also provided with a disc (16) having a diametergenerally corresponding to that of the interior of the housing (1). Disc(16) thus separates the cam (13) and reservoir drive mechanism(described below) from the through-going pathway (2) thus reducing therisk of ingress of medicament into the drive mechanism.

Drive sleeve (14) is also provided with a reservoir drive mechanism (notshown) which is adapted to rotate the medicament reservoir (7) through apredetermined angle relative to the housing (1), the angle of rotationbeing limited by a stop (17) provided on the exterior of the housing.

A helical blade (18) is fixedly mounted in the housing between thereservoir (7) and the mouthpiece (4), such that the blade (18) abutsagainst the face of the body of compacted medicament (8) contained inthe reservoir (7). The body of compacted medicament (8) is further urgedtowards blade (18) by a compression spring (19) which acts against theouter wall of medicament reservoir (7) and the interior of drive sleeve(14).

In use, drive sleeve (14) is rotated in the direction of arrow A inFIG. 1. The initial part of the rotation causes the cam (13) to movecarrier (11) axially within the housing (1) towards mouthpiece (4). Theshutter (9) thus moves from the first/rest position FIG. 1! to thesecond/metering position FIG. 2!. Once the compacted body (8) is incommunication with the through-going pathway (2), further rotationoperates the reservoir drive means (not shown) thus advancing thereservoir (7) and compacted body (8) through an angle of 60°, the degreeof rotation being limited by stop (17) provided on the outside of thehousing (1). As the reservoir (7) rotates helical blade (18) abrades apredetermined quantity of powdered medicament from the face of compactedbody (8).

The drive sleeve (14) is then rotated in the direction of arrow B inFIG. 2. Cam surface (13) rotates back to its original position allowingthe shutter (9) to return to its first/rest position under the bias ofcantilever (15). As the shutter (9) returns to the first/rest positionthe metal blade (10) severs the abraded dose of medicament from thecompacted body (8), the dose being deposited in holding chamber (20) inthe through-going pathway (2), the chamber (20) being defined in part bythe blade (18) and shutter (9). The patient then removes the mouthpiececover (not shown) and inhales at the mouthpiece (4) drawing air throughair inlet (3) and through-going pathway (2). The dose of medicamentdrawn into dispersion chamber (5) where it is entrained in the air flowand inhaled by the patient. During inhalation the shutter (9) preventsadditional medicament from being scoured from the compacted body (8)since it isolates the compacted body (8) from the through-going pathway(2).

I claim:
 1. A medicament inhalation device comprising a housing (1)having a through-going pathway (2) connecting an air inlet (3) with anair outlet (4), a medicament reservoir (7) for receiving a compactedbody of powdered medicament (8), and metering means for dispensing apredetermined dose of medicament from the reservoir (7) into thethrough-going pathway (2), the metering means including means (18) forabrading the compacted body (8) which extends into the reservoir 7;characterized in that the device is provided with a shutter (9) movablebetween a first position in which the reservoir (7) is isolated from thethrough-going pathway (2) and a second position in which the reservoir(7) is in communication with the through-going pathway (2) such that adose of medicament can be dispensed from the reservoir (7) into thethrough-going pathway (2).
 2. A device according to claim 1, wherein themedicament reservoir (7) contains a compacted body of powderedmedicament (8).
 3. A device according to claim 1, further comprisingmeans for biassing the shutter (9) into the first position in which thereservoir (7) is isolated from the through-going pathway (2).
 4. Adevice according claim 1, wherein the shutter (9) moves from the firstposition to the second position prior to the metering of a predetermineddose of medicament from the reservoir (7).
 5. A device according toclaim 4, further comprising means for biassing the shutter (9) to returnto the first position.
 6. A device according to claim 1, furthercomprising a carrier (11) on which the shutter (9) is mounted, thecarrier (11) arranged to move axially within the housing (1).
 7. Adevice according to claim 1, further comprising a cam (13) which ismounted in the housing to effect movement of the shutter (9).
 8. Adevice according to claim 7 further comprising a carrier (11) on whichthe shutter (9) is mounted, the carrier (11) arranged to move axiallywithin the housing (1).
 9. A device according to claim 1, wherein theshutter (9) is adapted to sever the metered dose of medicament from thereservoir (7) upon moving from the second to the first position.
 10. Adevice according to claim 9, wherein the shutter (9) comprises a metalblade (10).